1
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Brinzer RA, Winter AD, Page AP. The relationship between intraflagellar transport and upstream protein trafficking pathways and macrocyclic lactone resistance in Caenorhabditis elegans. G3 (BETHESDA, MD.) 2024; 14:jkae009. [PMID: 38227795 PMCID: PMC10917524 DOI: 10.1093/g3journal/jkae009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/08/2024] [Accepted: 01/08/2024] [Indexed: 01/18/2024]
Abstract
Parasitic nematodes are globally important and place a heavy disease burden on infected humans, crops, and livestock, while commonly administered anthelmintics used for treatment are being rendered ineffective by increasing levels of resistance. It has recently been shown in the model nematode Caenorhabditis elegans that the sensory cilia of the amphid neurons play an important role in resistance toward macrocyclic lactones such as ivermectin (an avermectin) and moxidectin (a milbemycin) either through reduced uptake or intertissue signaling pathways. This study interrogated the extent to which ciliary defects relate to macrocyclic lactone resistance and dye-filling defects using a combination of forward genetics and targeted resistance screening approaches and confirmed the importance of intraflagellar transport in this process. This approach also identified the protein trafficking pathways used by the downstream effectors and the components of the ciliary basal body that are required for effector entry into these nonmotile structures. In total, 24 novel C. elegans anthelmintic survival-associated genes were identified in this study. When combined with previously known resistance genes, there are now 46 resistance-associated genes that are directly involved in amphid, cilia, and intraflagellar transport function.
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Affiliation(s)
- Robert A Brinzer
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Scotland G61 1QH, UK
| | - Alan D Winter
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Scotland G61 1QH, UK
| | - Antony P Page
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Scotland G61 1QH, UK
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2
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Majeed M, Han H, Zhang K, Cao WX, Liao CP, Hobert O, Lu H. Toolkits for detailed and high-throughput interrogation of synapses in C. elegans. eLife 2024; 12:RP91775. [PMID: 38224479 PMCID: PMC10945580 DOI: 10.7554/elife.91775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2024] Open
Abstract
Visualizing synaptic connectivity has traditionally relied on time-consuming electron microscopy-based imaging approaches. To scale the analysis of synaptic connectivity, fluorescent protein-based techniques have been established, ranging from the labeling of specific pre- or post-synaptic components of chemical or electrical synapses to transsynaptic proximity labeling technology such as GRASP and iBLINC. In this paper, we describe WormPsyQi, a generalizable image analysis pipeline that automatically quantifies synaptically localized fluorescent signals in a high-throughput and robust manner, with reduced human bias. We also present a resource of 30 transgenic strains that label chemical or electrical synapses throughout the nervous system of the nematode Caenorhabditis elegans, using CLA-1, RAB-3, GRASP (chemical synapses), or innexin (electrical synapse) reporters. We show that WormPsyQi captures synaptic structures in spite of substantial heterogeneity in neurite morphology, fluorescence signal, and imaging parameters. We use these toolkits to quantify multiple obvious and subtle features of synapses - such as number, size, intensity, and spatial distribution of synapses - in datasets spanning various regions of the nervous system, developmental stages, and sexes. Although the pipeline is described in the context of synapses, it may be utilized for other 'punctate' signals, such as fluorescently tagged neurotransmitter receptors and cell adhesion molecules, as well as proteins in other subcellular contexts. By overcoming constraints on time, sample size, cell morphology, and phenotypic space, this work represents a powerful resource for further analysis of synapse biology in C. elegans.
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Affiliation(s)
- Maryam Majeed
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia UniversityNew YorkUnited States
| | - Haejun Han
- School of Electrical and Computer Engineering, Georgia Institute of TechnologyAtlantaUnited States
- The Parker H Petit Institute of Bioengineering and Bioscience, Georgia Institute of TechnologyAtlantaUnited States
| | - Keren Zhang
- School of Chemical and Biomolecular Engineering, Georgia Institute of TechnologyAtlantaUnited States
| | - Wen Xi Cao
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia UniversityNew YorkUnited States
| | - Chien-Po Liao
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia UniversityNew YorkUnited States
| | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia UniversityNew YorkUnited States
| | - Hang Lu
- The Parker H Petit Institute of Bioengineering and Bioscience, Georgia Institute of TechnologyAtlantaUnited States
- School of Chemical and Biomolecular Engineering, Georgia Institute of TechnologyAtlantaUnited States
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3
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Zhang X, Wang Y, Cai Z, Wan Z, Aihemaiti Y, Tu H. A gonadal gap junction INX-14/Notch GLP-1 signaling axis suppresses gut defense through an intestinal lysosome pathway. Front Immunol 2023; 14:1249436. [PMID: 37928537 PMCID: PMC10620905 DOI: 10.3389/fimmu.2023.1249436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 10/03/2023] [Indexed: 11/07/2023] Open
Abstract
Gap junctions mediate intercellular communications across cellular networks in the nervous and immune systems. Yet their roles in intestinal innate immunity are poorly understood. Here, we show that the gap junction/innexin subunit inx-14 acts in the C. elegans gonad to attenuate intestinal defenses to Pseudomonas aeruginosa PA14 infection through the PMK-1/p38 pathway. RNA-Seq analyses revealed that germline-specific inx-14 RNAi downregulated Notch/GLP-1 signaling, while lysosome and PMK-1/p38 pathways were upregulated. Consistently, disruption of inx-14 or glp-1 in the germline enhanced resistance to PA14 infection and upregulated lysosome and PMK-1/p38 activity. We show that lysosome signaling functions downstream of the INX-14/GLP-1 signaling axis and upstream of PMK-1/p38 pathway to facilitate intestinal defense. Our findings expand the understanding of the links between the reproductive system and intestinal defense, which may be evolutionarily conserved in higher organism.
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Affiliation(s)
| | | | | | | | | | - Haijun Tu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan, China
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4
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Kochersberger A, Torkashvand MM, Lee D, Baskoylu S, Sengupta T, Koonce N, Emerson CE, Patel NV, Colón-Ramos D, Flavell S, Horvitz HR, Venkatachalam V, Hammarlund M. Programmed Cell Death Modifies Neural Circuits and Tunes Intrinsic Behavior. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.11.557249. [PMID: 37745399 PMCID: PMC10515839 DOI: 10.1101/2023.09.11.557249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Programmed cell death is a common feature of animal development. During development of the C. elegans hermaphrodite, programmed cell death (PCD) removes 131 cells from stereotyped positions in the cell lineage, mostly in neuronal lineages. Blocking cell death results in supernumerary "undead" neurons. We find that undead neurons can be wired into circuits, can display activity, and can modify specific behaviors. The two undead RIM-like neurons participate in the RIM-containing circuit that computes movement. The addition of these two extra neurons results in animals that initiate fewer reversals and lengthens the duration of those reversals that do occur. We describe additional behavioral alterations of cell-death mutants, including in turning angle and pharyngeal pumping. These findings reveal that, like too much PCD, too little PCD can modify nervous system function and animal behavior.
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Affiliation(s)
- Alison Kochersberger
- Department of Genetics and Department of Neuroscience, Yale University School of Medicine; New Haven, CT 06536, USA
| | | | - Dongyeop Lee
- Howard Hughes Medical Institute, Department of Biology, MIT; Cambridge, MA 02139, USA
| | - Saba Baskoylu
- Picower Institute for Learning and Memory, MIT; Cambridge, MA 02139, USA
| | - Titas Sengupta
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
| | - Noelle Koonce
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
| | - Chloe E Emerson
- Department of Genetics and Department of Neuroscience, Yale University School of Medicine; New Haven, CT 06536, USA
| | - Nandan V Patel
- Department of Genetics and Department of Neuroscience, Yale University School of Medicine; New Haven, CT 06536, USA
| | - Daniel Colón-Ramos
- Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine; New Haven, CT 06536, USA
- MBL Fellows, Marine Biological Laboratory; Woods Hole, MA 02543, USA
- Instituto de Neurobiología, Recinto de Ciencias Médicas, Universidad de Puerto Rico; San Juan 00901, Puerto Rico
| | - Steven Flavell
- Picower Institute for Learning and Memory, MIT; Cambridge, MA 02139, USA
| | - H Robert Horvitz
- Howard Hughes Medical Institute, Department of Biology, MIT; Cambridge, MA 02139, USA
| | | | - Marc Hammarlund
- Department of Genetics and Department of Neuroscience, Yale University School of Medicine; New Haven, CT 06536, USA
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5
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Zhan X, Chen C, Niu L, Du X, Lei Y, Dan R, Wang ZW, Liu P. Locomotion modulates olfactory learning through proprioception in C. elegans. Nat Commun 2023; 14:4534. [PMID: 37500635 PMCID: PMC10374624 DOI: 10.1038/s41467-023-40286-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 07/19/2023] [Indexed: 07/29/2023] Open
Abstract
Locomotor activities can enhance learning, but the underlying circuit and synaptic mechanisms are largely unknown. Here we show that locomotion facilitates aversive olfactory learning in C. elegans by activating mechanoreceptors in motor neurons, and transmitting the proprioceptive information thus generated to locomotion interneurons through antidromic-rectifying gap junctions. The proprioceptive information serves to regulate experience-dependent activities and functional coupling of interneurons that process olfactory sensory information to produce the learning behavior. Genetic destruction of either the mechanoreceptors in motor neurons, the rectifying gap junctions between the motor neurons and locomotion interneurons, or specific inhibitory synapses among the interneurons impairs the aversive olfactory learning. We have thus uncovered an unexpected role of proprioception in a specific learning behavior as well as the circuit, synaptic, and gene bases for this function.
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Affiliation(s)
- Xu Zhan
- Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China and Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China
| | - Chao Chen
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, Hubei, China
- Department of Orthopaedics, Hefeng Central Hospital, 445800, Enshi, Hubei, China
| | - Longgang Niu
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, 06030, USA
| | - Xinran Du
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, 06030, USA
| | - Ying Lei
- Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China and Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China
| | - Rui Dan
- Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China and Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China
| | - Zhao-Wen Wang
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, 06030, USA.
| | - Ping Liu
- Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China and Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China.
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6
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Sun H, Hobert O. Temporal transitions in the postembryonic nervous system of the nematode Caenorhabditis elegans: Recent insights and open questions. Semin Cell Dev Biol 2023; 142:67-80. [PMID: 35688774 DOI: 10.1016/j.semcdb.2022.05.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/27/2022] [Accepted: 05/27/2022] [Indexed: 10/18/2022]
Abstract
After the generation, differentiation and integration into functional circuitry, post-mitotic neurons continue to change certain phenotypic properties throughout postnatal juvenile stages until an animal has reached a fully mature state in adulthood. We will discuss such changes in the context of the nervous system of the nematode C. elegans, focusing on recent descriptions of anatomical and molecular changes that accompany postembryonic maturation of neurons. We summarize the characterization of genetic timer mechanisms that control these temporal transitions or maturational changes, and discuss that many but not all of these transitions relate to sexual maturation of the animal. We describe how temporal, spatial and sex-determination pathways are intertwined to sculpt the emergence of cell-type specific maturation events. Finally, we lay out several unresolved questions that should be addressed to move the field forward, both in C. elegans and in vertebrates.
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Affiliation(s)
- Haosheng Sun
- Department of Cell, Developmental, and Integrative Biology. University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Oliver Hobert
- Department of Biological Sciences, Columbia University, New York, USA
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7
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Positive interaction between ASH and ASK sensory neurons accelerates nociception and inhibits behavioral adaptation. iScience 2022; 25:105287. [PMID: 36304123 PMCID: PMC9593764 DOI: 10.1016/j.isci.2022.105287] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 05/22/2022] [Accepted: 10/04/2022] [Indexed: 11/23/2022] Open
Abstract
Central and peripheral sensory neurons tightly regulate nociception and avoidance behavior. The peripheral modulation of nociception provides more veridical and instantaneous information for animals to achieve rapid, more fine-tuned and concentrated behavioral responses. In this study, we find that positive interaction between ASH and ASK sensory neurons is essential for the fast-rising phase of ASH Ca2+ responses to noxious copper ions and inhibits the adaption of avoiding Cu2+. We reveal the underlying neuronal circuit mechanism. ASK accelerates the ASH Ca2+ responses by transferring cGMP through gap junctions. ASH excites ASK via a disinhibitory neuronal circuit composed of ASH, AIA, and ASK. Avoidance adaptation depends on the slope rate of the rising phase of ASH Ca2+ responses. Thus, in addition to amplitude, sensory kinetics is significant for sensations and behaviors, especially for sensory and behavioral adaptations.
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8
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Post-gastrulation transition from whole-body to tissue-specific intercellular calcium signaling in the appendicularian tunicate Oikopleuradioica. Dev Biol 2022; 492:37-46. [PMID: 36162551 DOI: 10.1016/j.ydbio.2022.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 07/09/2022] [Accepted: 09/17/2022] [Indexed: 11/21/2022]
Abstract
We recently described calcium signaling in the appendicularian tunicate Oikopleura dioica during pre-gastrulation stages, and showed that regularly occurring calcium waves progress throughout the embryo in a characteristic spatiotemporal pattern from an initiation site in muscle lineage blastomeres (Mikhaleva et al., 2019). Here, we have extended our observations to the period spanning from gastrulation to post-hatching stages. We find that repetitive Ca2+ waves persist throughout this developmental window, albeit with a gradual increase in frequency. The initiation site of the waves shifts from muscle cells at gastrulation and early tailbud stages, to the central nervous system at late tailbud and post-hatching stages, indicating a transition from muscle-driven to neurally driven events as tail movements emerge. At these later stages, both the voltage gated Na + channel blocker tetrodotoxin (TTX) and the T-type Ca2+ channel blocker and nAChR antagonist mecamylamine eliminate tail movements. At late post-hatching stages, mecamylamine blocks Ca2+ signals in the muscles but not the central nervous system. Post-gastrulation Ca2+ signals also arise in epithelial cells, first in a haphazard pattern in scattered cells during tailbud stages, evolving after hatching into repetitive rostrocaudal waves with a different frequency than the nervous system-to-muscle waves, and insensitive to mecamylamine. The desynchronization of Ca2+ waves arising in different parts of the body indicates a shift from whole-body to tissue/organ-specific Ca2+ signaling dynamics as organogenesis occurs, with neurally driven Ca2+ signaling dominating at the later stages when behavior emerges.
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9
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Santella A, Kolotuev I, Kizilyaprak C, Bao Z. Cross-modality synthesis of EM time series and live fluorescence imaging. eLife 2022; 11:77918. [PMID: 35666127 PMCID: PMC9213002 DOI: 10.7554/elife.77918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/05/2022] [Indexed: 11/13/2022] Open
Abstract
Analyses across imaging modalities allow the integration of complementary spatiotemporal information about brain development, structure, and function. However, systematic atlasing across modalities is limited by challenges to effective image alignment. We combine highly spatially resolved electron microscopy (EM) and highly temporally resolved time-lapse fluorescence microscopy (FM) to examine the emergence of a complex nervous system in Caenorhabditis elegans embryogenesis. We generate an EM time series at four classic developmental stages and create a landmark-based co-optimization algorithm for cross-modality image alignment, which handles developmental heterochrony among datasets to achieve accurate single-cell level alignment. Synthesis based on the EM series and time-lapse FM series carrying different cell-specific markers reveals critical dynamic behaviors across scales of identifiable individual cells in the emergence of the primary neuropil, the nerve ring, as well as a major sensory organ, the amphid. Our study paves the way for systematic cross-modality data synthesis in C. elegans and demonstrates a powerful approach that may be applied broadly.
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Affiliation(s)
- Anthony Santella
- Molecular Cytology Core, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Irina Kolotuev
- Electron Microscopy Facility, University of Lausanne, Lausanne, Switzerland
| | | | - Zhirong Bao
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States
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10
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Niu B, Nguyen Bach T, Chen X, Raghunath Chandratre K, Isaac Murray J, Zhao Z, Zhang M. Computational modeling and analysis of the morphogenetic domain signaling networks regulating C. elegans embryogenesis. Comput Struct Biotechnol J 2022; 20:3653-3666. [PMID: 35891777 PMCID: PMC9289785 DOI: 10.1016/j.csbj.2022.05.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 05/29/2022] [Accepted: 05/30/2022] [Indexed: 11/03/2022] Open
Abstract
Caenorhabditis elegans, often referred to as the ‘roundworm’, provides a powerful model for studying cell autonomous and cell–cell interactions through the direct observation of embryonic development in vivo. By leveraging the precisely mapped cell lineage at single cell resolution, we are able to study at a systems level how early embryonic cells communicate across morphogenetic domains for the coordinated processes of gene expressions and collective cellular behaviors that regulate tissue morphogenesis. In this study, we developed a computational framework for the exploration of the morphogenetic domain cell signaling networks that may regulate C. elegans gastrulation and embryonic organogenesis. We demonstrated its utility by producing the following results, i) established a virtual reference model of developing C. elegans embryos through the spatiotemporal alignment of individual embryo cell nuclear imaging samples; ii) integrated the single cell spatiotemporal gene expression profile with the established virtual embryo model by data pooling; iii) trained a Machine Learning model (Random Forest Regression), which predicts accurately the spatial positions of the cells given their gene expression profiles for a given developmental time (e.g. total cell number of the embryo); iv) enabled virtual 4-dimensional tomographic graphical modeling of single cell data; v) inferred the biology signaling pathways that act in each of morphogenetic domains by meta-data analysis. It is intriguing that the morphogenetic domain cell signaling network seems to involve some crosstalk of multiple biology signaling pathways during the formation of tissue boundary pattern. Lastly, we developed the Software tool ‘Embryo aligner version 1.0’ and provided it as an Open Source program to the research community for virtual embryo modeling, and phenotype perturbation analyses (https://github.com/csniuben/embryo_aligner/wiki and https://bioinfo89.github.io/C.elegansEmbryonicOrganogenesisweb/).
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A single chemosensory GPCR is required for a concentration-dependent behavioral switching in C. elegans. Curr Biol 2021; 32:398-411.e4. [PMID: 34906353 DOI: 10.1016/j.cub.2021.11.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 10/15/2021] [Accepted: 11/12/2021] [Indexed: 12/19/2022]
Abstract
Animals detect and discriminate countless environmental chemicals for their well-being and survival. Although a single chemical can trigger opposing behavioral responses depending on its concentration, the mechanisms underlying such a concentration-dependent switching remain poorly understood. Here, we show that C. elegans exhibits either attraction or avoidance of the bacteria-derived volatile chemical dimethyl trisulfide (DMTS) depending on its concentration. This behavioral switching is mediated by two different types of chemosensory neurons, both of which express the DMTS-sensitive seven-transmembrane G protein-coupled receptor (GPCR) SRI-14. These two sensory neurons share downstream interneurons that process and translate DMTS signals via distinct glutamate receptors to generate the appropriate behavioral outcome. Thus, our results present one mechanism by which an animal connects two distinct types of chemosensory neurons detecting a common ligand to alternate downstream circuitry, thus efficiently switching between specific behavioral programs based on ligand concentration.
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12
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Hsieh YW, Xiong R, Chuang CF. Synergistic roles of homeodomain proteins UNC-62 homothorax and MLS-2 HMX/NKX in the specification of olfactory neurons in Caenorhabditis elegans. Genetics 2021; 219:6350488. [PMID: 34849889 DOI: 10.1093/genetics/iyab133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 08/09/2021] [Indexed: 11/13/2022] Open
Abstract
General identity of the Caenorhabditis elegans AWC olfactory neuron pair is specified by the OTX/OTD transcription factor CEH-36 and the HMG-box transcription factor SOX-2, followed by asymmetrical differentiation of the pair into two distinct subtypes, default AWCOFF and induced AWCON, through a stochastic signaling event. The HMX/NKX transcription factor MLS-2 regulates the expression of ceh-36 to specify general AWC identity. However, general AWC identity is lost in only one of the two AWC cells in the majority of mls-2 null mutants displaying defective general AWC identity, suggesting that additional transcription factors have a partially overlapping role with MLS-2 in the specification of general AWC identity. Here, we identify a role of unc-62, encoding a homothorax/Meis/TALE homeodomain protein, in the specification of general AWC identity. As in mls-2 null mutants, unc-62 null mutants showed an incomplete penetrance in loss of general AWC identity. However, unc-62; mls-2 double mutants display a nearly complete penetrance of identity loss in both AWC cells. Thus, unc-62 and mls-2 have a partially overlapping function in the specification of general AWC identity. Furthermore, our genetic results suggest that mls-2 and unc-62 act cell autonomously in promoting the AWCON subtype. Together, our findings reveal the sequential roles of the unc-62 and mls-2 pair in AWC development, specification of general AWC identity in early embryogenesis, and asymmetric differentiation of AWC subtypes in late embryogenesis.
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Affiliation(s)
- Yi-Wen Hsieh
- Department of Biological Sciences, University of Illinois at Chicago, IL 60607, USA
| | - Rui Xiong
- Department of Biological Sciences, University of Illinois at Chicago, IL 60607, USA
| | - Chiou-Fen Chuang
- Department of Biological Sciences, University of Illinois at Chicago, IL 60607, USA.,Graduate Program in Neuroscience, University of Illinois at Chicago, IL 60607, USA
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13
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Zhu Y, Wang S, Gong X, Edmiston EK, Zhong S, Li C, Zhao P, Wei S, Jiang X, Qin Y, Kang J, Wang Y, Sun Q, Gong G, Wang F, Tang Y. Associations between hemispheric asymmetry and schizophrenia-related risk genes in people with schizophrenia and people at a genetic high risk of schizophrenia. Br J Psychiatry 2021; 219:392-400. [PMID: 35048853 PMCID: PMC8529637 DOI: 10.1192/bjp.2021.47] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Schizophrenia is considered a polygenic disorder. People with schizophrenia and those with genetic high risk of schizophrenia (GHR) have presented with similar neurodevelopmental deficits in hemispheric asymmetry. The potential associations between neurodevelopmental abnormalities and schizophrenia-related risk genes in both schizophrenia and those with GHR remains unclear. AIMS To investigate the shared and specific alternations to the structural network in people with schizophrenia and those with GHR. And to identify an association between vulnerable structural network alternation and schizophrenia-related risk genes. METHOD A total of 97 participants with schizophrenia, 79 participants with GHR and 192 healthy controls, underwent diffusion tensor imaging (DTI) scans at a single site. We used graph theory to characterise hemispheric and whole-brain structural network topological metrics. For 26 people in the schizophrenia group and 48 in the GHR group with DTI scans we also calculated their schizophrenia-related polygenic risk scores (SZ-PRSs). The correlations between alterations to the structural network and SZ-PRSs were calculated. Based on the identified genetic-neural association, bioinformatics enrichment was explored. RESULTS There were significant hemispheric asymmetric deficits of nodal efficiency, global and local efficiency in the schizophrenia and GHR groups. Hemispheric asymmetric deficit of local efficiency was significantly positively correlated with SZ-PRSs in the schizophrenia and GHR groups. Bioinformatics enrichment analysis showed that these risk genes may be linked to signal transduction, neural development and neuron structure. The schizophrenia group showed a significant decrease in the whole-brain structural network. CONCLUSIONS The shared asymmetric deficits in people with schizophrenia and those with GHR, and the association between anomalous asymmetry and SZ-PRSs suggested a vulnerability imaging marker regulated by schizophrenia-related risk genes. Our findings provide new insights into asymmetry regulated by risk genes and provides a better understanding of the genetic-neural pathological underpinnings of schizophrenia.
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Affiliation(s)
- Yue Zhu
- Department of Psychiatry, The First Affiliated Hospital of China Medical University, PR China; and Brain Function Research Section, The First Affiliated Hospital of China Medical University, PR China
| | - Shuai Wang
- Department of Psychiatry, The First Affiliated Hospital of China Medical University, PR China; Brain Function Research Section, The First Affiliated Hospital of China Medical University, PR China; and Department of Psychology, Weifang Medical University, PR China
| | - Xiaohong Gong
- State Key Laboratory of Genetic Engineering and Human Phenome Institute, School of Life Sciences, Fudan University, PR China
| | | | - Suyu Zhong
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, PR China
| | - Chao Li
- Brain Function Research Section, The First Affiliated Hospital of China Medical University, PR China; and Department of Radiology, The First Affiliated Hospital of China Medical University, PR China
| | - Pengfei Zhao
- Department of Psychiatry, The First Affiliated Hospital of China Medical University, PR China; and Brain Function Research Section, The First Affiliated Hospital of China Medical University, PR China
| | - Shengnan Wei
- Brain Function Research Section, The First Affiliated Hospital of China Medical University, PR China; and Department of Radiology, The First Affiliated Hospital of China Medical University, PR China
| | - Xiaowei Jiang
- Brain Function Research Section, The First Affiliated Hospital of China Medical University, PR China; and Department of Radiology, The First Affiliated Hospital of China Medical University, PR China
| | - Yue Qin
- State Key Laboratory of Genetic Engineering and Human Phenome Institute, School of Life Sciences, Fudan University, PR China
| | - Jujiao Kang
- State Key Laboratory of Genetic Engineering and Human Phenome Institute, School of Life Sciences, Fudan University, PR China
| | - Yi Wang
- State Key Laboratory of Genetic Engineering and Human Phenome Institute, School of Life Sciences, Fudan University, PR China
| | - Qikun Sun
- Department of Radiation Oncology, The First Affiliated Hospital of China Medical University, PR China
| | - Gaolang Gong
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, PR China
| | - Fei Wang
- Department of Psychiatry, The First Affiliated Hospital of China Medical University, PR China; Brain Function Research Section, The First Affiliated Hospital of China Medical University, PR China; Department of Radiology, The First Affiliated Hospital of China Medical University, PR China; and Department of Psychiatry, Yale School of Medicine, USA
| | - Yanqing Tang
- Department of Psychiatry, The First Affiliated Hospital of China Medical University, PR China; Brain Function Research Section, The First Affiliated Hospital of China Medical University, PR China; and Department of Geriatrics, The First Affiliated Hospital of China Medical University, PR China,Correspondence: Yanqing Tang.
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14
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Srivastava P, Kane A, Harrison C, Levin M. A Meta-Analysis of Bioelectric Data in Cancer, Embryogenesis, and Regeneration. Bioelectricity 2021; 3:42-67. [PMID: 34476377 DOI: 10.1089/bioe.2019.0034] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Developmental bioelectricity is the study of the endogenous role of bioelectrical signaling in all cell types. Resting potentials and other aspects of ionic cell physiology are known to be important regulatory parameters in embryogenesis, regeneration, and cancer. However, relevant quantitative measurement and genetic phenotyping data are distributed throughout wide-ranging literature, hampering experimental design and hypothesis generation. Here, we analyze published studies on bioelectrics and transcriptomic and genomic/phenotypic databases to provide a novel synthesis of what is known in three important aspects of bioelectrics research. First, we provide a comprehensive list of channelopathies-ion channel and pump gene mutations-in a range of important model systems with developmental patterning phenotypes, illustrating the breadth of channel types, tissues, and phyla (including man) in which bioelectric signaling is a critical endogenous aspect of embryogenesis. Second, we perform a novel bioinformatic analysis of transcriptomic data during regeneration in diverse taxa that reveals an electrogenic protein to be the one common factor specifically expressed in regeneration blastemas across Kingdoms. Finally, we analyze data on distinct Vmem signatures in normal and cancer cells, revealing a specific bioelectrical signature corresponding to some types of malignancies. These analyses shed light on fundamental questions in developmental bioelectricity and suggest new avenues for research in this exciting field.
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Affiliation(s)
- Pranjal Srivastava
- Rye High School, Rye, New York, USA; Current Affiliation: College of Chemistry, University of California, Berkeley, Berkeley, California, USA
| | - Anna Kane
- Department of Biology, Allen Discovery Center, Tufts University, Medford, Massachusetts, USA
| | - Christina Harrison
- Department of Biology, Allen Discovery Center, Tufts University, Medford, Massachusetts, USA
| | - Michael Levin
- Department of Biology, Allen Discovery Center, Tufts University, Medford, Massachusetts, USA
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15
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Kovács IA, Barabási DL, Barabási AL. Uncovering the genetic blueprint of the C. elegans nervous system. Proc Natl Acad Sci U S A 2020; 117:33570-33577. [PMID: 33318182 PMCID: PMC7777131 DOI: 10.1073/pnas.2009093117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Despite rapid advances in connectome mapping and neuronal genetics, we lack theoretical and computational tools to unveil, in an experimentally testable fashion, the genetic mechanisms that govern neuronal wiring. Here we introduce a computational framework to link the adjacency matrix of a connectome to the expression patterns of its neurons, helping us uncover a set of genetic rules that govern the interactions between neurons in contact. The method incorporates the biological realities of the system, accounting for noise from data collection limitations, as well as spatial restrictions. The resulting methodology allows us to infer a network of 19 innexin interactions that govern the formation of gap junctions in Caenorhabditis elegans, five of which are already supported by experimental data. As advances in single-cell gene expression profiling increase the accuracy and the coverage of the data, the developed framework will allow researchers to systematically infer experimentally testable connection rules, offering mechanistic predictions for synapse and gap junction formation.
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Affiliation(s)
- István A Kovács
- Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208
- Department of Data and Network Science, Central European University, Budapest 1051, Hungary
- Network Science Institute, Northeastern University, Boston, MA 02115
- Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, Budapest 1121, Hungary
| | | | - Albert-László Barabási
- Department of Data and Network Science, Central European University, Budapest 1051, Hungary;
- Network Science Institute, Northeastern University, Boston, MA 02115
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
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16
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Miller AC, Urban EA, Lyons EL, Herman TG, Johnston RJ. Interdependent regulation of stereotyped and stochastic photoreceptor fates in the fly eye. Dev Biol 2020; 471:89-96. [PMID: 33333066 PMCID: PMC7856283 DOI: 10.1016/j.ydbio.2020.12.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 12/07/2020] [Accepted: 12/09/2020] [Indexed: 12/14/2022]
Abstract
Diversification of neuronal subtypes often requires stochastic gene regulatory mechanisms. How stochastically expressed transcription factors interact with other regulators in gene networks to specify cell fates is poorly understood. The random mosaic of color-detecting R7 photoreceptor subtypes in Drosophila is controlled by the stochastic on/off expression of the transcription factor Spineless (Ss). In SsON R7s, Ss induces expression of Rhodopsin 4 (Rh4), whereas in SsOFF R7s, the absence of Ss allows expression of Rhodopsin 3 (Rh3). Here, we find that the transcription factor Runt, which is initially expressed in all R7s, is sufficient to promote stochastic Ss expression. Later, as R7s develop, Ss negatively feeds back onto Runt to prevent repression of Rh4 and ensure proper fate specification. Together, stereotyped and stochastic regulatory inputs are integrated into feedforward and feedback mechanisms to control cell fate.
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Affiliation(s)
- Adam C Miller
- Institute of Molecular Biology, University of Oregon, Eugene, OR, 97403, USA
| | - Elizabeth A Urban
- Department of Biology, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD, 21218-2685, USA
| | - Eric L Lyons
- Institute of Molecular Biology, University of Oregon, Eugene, OR, 97403, USA
| | - Tory G Herman
- Institute of Molecular Biology, University of Oregon, Eugene, OR, 97403, USA.
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD, 21218-2685, USA.
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17
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Meng L, Yan D. NLR-1/CASPR Anchors F-Actin to Promote Gap Junction Formation. Dev Cell 2020; 55:574-587.e3. [PMID: 33238150 DOI: 10.1016/j.devcel.2020.10.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 08/05/2020] [Accepted: 10/28/2020] [Indexed: 12/31/2022]
Abstract
Gap junctions are present in most tissues and play essential roles in various biological processes. However, we know surprisingly little about the molecular mechanisms underlying gap junction formation. Here, we uncover the essential role of a conserved EGF- and laminin-G-domain-containing protein nlr-1/CASPR in the regulation of gap junction formation in multiple tissues across different developmental stages in C. elegans. NLR-1 is located in the gap junction perinexus, a region adjacent to but not overlapping with gap junctions, and forms puncta before the clusters of gap junction channels appear on the membrane. We show that NLR-1 can directly bind to actin to recruit F-actin networks at the gap junction formation plaque, and the formation of F-actin patches plays a critical role in the assembly of gap junction channels. Our findings demonstrate that nlr-1/CASPR acts as an early stage signal for gap junction formation through anchoring of F-actin networks.
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Affiliation(s)
- Lingfeng Meng
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Dong Yan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology, Regeneration Next, and Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC 27710, USA.
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18
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GABAergic motor neurons bias locomotor decision-making in C. elegans. Nat Commun 2020; 11:5076. [PMID: 33033264 PMCID: PMC7544903 DOI: 10.1038/s41467-020-18893-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 09/17/2020] [Indexed: 12/18/2022] Open
Abstract
Proper threat-reward decision-making is critical to animal survival. Emerging evidence indicates that the motor system may participate in decision-making but the neural circuit and molecular bases for these functions are little known. We found in C. elegans that GABAergic motor neurons (D-MNs) bias toward the reward behavior in threat-reward decision-making by retrogradely inhibiting a pair of premotor command interneurons, AVA, that control cholinergic motor neurons in the avoidance neural circuit. This function of D-MNs is mediated by a specific ionotropic GABA receptor (UNC-49) in AVA, and depends on electrical coupling between the two AVA interneurons. Our results suggest that AVA are hub neurons where sensory inputs from threat and reward sensory modalities and motor information from D-MNs are integrated. This study demonstrates at single-neuron resolution how motor neurons may help shape threat-reward choice behaviors through interacting with other neurons.
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19
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Alicea B. Raising the Connectome: The Emergence of Neuronal Activity and Behavior in Caenorhabditis elegans. Front Cell Neurosci 2020; 14:524791. [PMID: 33100971 PMCID: PMC7522492 DOI: 10.3389/fncel.2020.524791] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 08/24/2020] [Indexed: 11/15/2022] Open
Abstract
The differentiation of neurons and formation of connections between cells is the basis of both the adult phenotype and behaviors tied to cognition, perception, reproduction, and survival. Such behaviors are associated with local (circuits) and global (connectome) brain networks. A solid understanding of how these networks emerge is critical. This opinion piece features a guided tour of early developmental events in the emerging connectome, which is crucial to a new view on the connectogenetic process. Connectogenesis includes associating cell identities with broader functional and developmental relationships. During this process, the transition from developmental cells to terminally differentiated cells is defined by an accumulation of traits that ultimately results in neuronal-driven behavior. The well-characterized developmental and cell biology of Caenorhabditis elegans will be used to build a synthesis of developmental events that result in a functioning connectome. Specifically, our view of connectogenesis enables a first-mover model of synaptic connectivity to be demonstrated using data representing larval synaptogenesis. In a first-mover model of Stackelberg competition, potential pre- and postsynaptic relationships are shown to yield various strategies for establishing various types of synaptic connections. By comparing these results to what is known regarding principles for establishing complex network connectivity, these strategies are generalizable to other species and developmental systems. In conclusion, we will discuss the broader implications of this approach, as what is presented here informs an understanding of behavioral emergence and the ability to simulate related biological phenomena.
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Affiliation(s)
- Bradly Alicea
- Orthogonal Research and Education Laboratory, Champaign, IL, United States
- OpenWorm Foundation, Boston, MA, United States
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20
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Jin EJ, Park S, Lyu X, Jin Y. Gap junctions: historical discoveries and new findings in the Caenorhabditiselegans nervous system. Biol Open 2020; 9:bio053983. [PMID: 32883654 PMCID: PMC7489761 DOI: 10.1242/bio.053983] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Gap junctions are evolutionarily conserved structures at close membrane contacts between two cells. In the nervous system, they mediate rapid, often bi-directional, transmission of signals through channels called innexins in invertebrates and connexins in vertebrates. Connectomic studies from Caenorhabditis elegans have uncovered a vast number of gap junctions present in the nervous system and non-neuronal tissues. The genome also has 25 innexin genes that are expressed in spatial and temporal dynamic pattern. Recent findings have begun to reveal novel roles of innexins in the regulation of multiple processes during formation and function of neural circuits both in normal conditions and under stress. Here, we highlight the diverse roles of gap junctions and innexins in the C. elegans nervous system. These findings contribute to fundamental understanding of gap junctions in all animals.
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Affiliation(s)
- Eugene Jennifer Jin
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Seungmee Park
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Xiaohui Lyu
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yishi Jin
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
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21
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Foster KJ, Cheesman HK, Liu P, Peterson ND, Anderson SM, Pukkila-Worley R. Innate Immunity in the C. elegans Intestine Is Programmed by a Neuronal Regulator of AWC Olfactory Neuron Development. Cell Rep 2020; 31:107478. [PMID: 32268082 PMCID: PMC7215899 DOI: 10.1016/j.celrep.2020.03.042] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 01/15/2020] [Accepted: 03/13/2020] [Indexed: 12/22/2022] Open
Abstract
Olfactory neurons allow animals to discriminate nutritious food sources from potential pathogens. From a forward genetic screen, we uncovered a surprising requirement for the olfactory neuron gene olrn-1 in the regulation of intestinal epithelial immunity in Caenorhabditis elegans. During nematode development, olrn-1 is required to program the expression of odorant receptors in the AWC olfactory neuron pair. Here, we show that olrn-1 also functions in AWC neurons in the cell non-autonomous suppression of the canonical p38 MAPK PMK-1 immune pathway in the intestine. Low activity of OLRN-1, which activates the p38 MAPK signaling cassette in AWC neurons during larval development, also de-represses the p38 MAPK PMK-1 pathway in the intestine to promote immune effector transcription, increased clearance of an intestinal pathogen, and resistance to bacterial infection. These data reveal an unexpected connection between olfactory receptor development and innate immunity and show that anti-pathogen defenses in the intestine are developmentally programmed.
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Affiliation(s)
- Kyle J Foster
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Hilary K Cheesman
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Pengpeng Liu
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Nicholas D Peterson
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Sarah M Anderson
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Read Pukkila-Worley
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01655, USA; Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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22
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Mutlu AS, Gao SM, Zhang H, Wang MC. Olfactory specificity regulates lipid metabolism through neuroendocrine signaling in Caenorhabditis elegans. Nat Commun 2020; 11:1450. [PMID: 32193370 PMCID: PMC7081233 DOI: 10.1038/s41467-020-15296-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 02/20/2020] [Indexed: 01/01/2023] Open
Abstract
Olfactory and metabolic dysfunctions are intertwined phenomena associated with obesity and neurodegenerative diseases; yet how mechanistically olfaction regulates metabolic homeostasis remains unclear. Specificity of olfactory perception integrates diverse environmental odors and olfactory neurons expressing different receptors. Here, we report that specific but not all olfactory neurons actively regulate fat metabolism without affecting eating behaviors in Caenorhabditis elegans, and identified specific odors that reduce fat mobilization via inhibiting these neurons. Optogenetic activation or inhibition of the responsible olfactory neural circuit promotes the loss or gain of fat storage, respectively. Furthermore, we discovered that FLP-1 neuropeptide released from this olfactory neural circuit signals through peripheral NPR-4/neuropeptide receptor, SGK-1/serum- and glucocorticoid-inducible kinase, and specific isoforms of DAF-16/FOXO transcription factor to regulate fat storage. Our work reveals molecular mechanisms underlying olfactory regulation of fat metabolism, and suggests the association between olfactory perception specificity of each individual and his/her susceptibility to the development of obesity.
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Affiliation(s)
- Ayse Sena Mutlu
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX, 77030, USA.
- Graduate Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Shihong Max Gao
- Graduate Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Haining Zhang
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Meng C Wang
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX, 77030, USA.
- Graduate Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA.
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX, 77030, USA.
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23
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Huizar F, Soundarrajan D, Paravitorghabeh R, Zartman J. Interplay between morphogen-directed positional information systems and physiological signaling. Dev Dyn 2020; 249:328-341. [PMID: 31794137 PMCID: PMC7328709 DOI: 10.1002/dvdy.140] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 11/20/2019] [Accepted: 11/22/2019] [Indexed: 12/16/2022] Open
Abstract
The development of an organism from an undifferentiated single cell into a spatially complex structure requires spatial patterning of cell fates across tissues. Positional information, proposed by Lewis Wolpert in 1969, has led to the characterization of many components involved in regulating morphogen signaling activity. However, how morphogen gradients are established, maintained, and interpreted by cells still is not fully understood. Quantitative and systems-based approaches are increasingly needed to define general biological design rules that govern positional information systems in developing organisms. This short review highlights a selective set of studies that have investigated the roles of physiological signaling in modulating and mediating morphogen-based pattern formation. Similarities between neural transmission and morphogen-based pattern formation mechanisms suggest underlying shared principles of active cell-based communication. Within larger tissues, neural networks provide directed information, via physiological signaling, that supplements positional information through diffusion. Further, mounting evidence demonstrates that physiological signaling plays a role in ensuring robustness of morphogen-based signaling. We conclude by highlighting several outstanding questions regarding the role of physiological signaling in morphogen-based pattern formation. Elucidating how physiological signaling impacts positional information is critical for understanding the close coupling of developmental and cellular processes in the context of development, disease, and regeneration.
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Affiliation(s)
- Francisco Huizar
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, South Bend, Indiana
- Bioengineering Graduate Program, University of Notre Dame, South Bend, Indiana
| | - Dharsan Soundarrajan
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, South Bend, Indiana
| | - Ramezan Paravitorghabeh
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, South Bend, Indiana
| | - Jeremiah Zartman
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, South Bend, Indiana
- Bioengineering Graduate Program, University of Notre Dame, South Bend, Indiana
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24
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A universal transportin protein drives stochastic choice of olfactory neurons via specific nuclear import of a sox-2-activating factor. Proc Natl Acad Sci U S A 2019; 116:25137-25146. [PMID: 31767767 DOI: 10.1073/pnas.1908168116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Stochastic neuronal cell fate choice involving notch-independent mechanisms is a poorly understood biological process. The Caenorhabditis elegans AWC olfactory neuron pair asymmetrically differentiates into the default AWCOFF and induced AWCON subtypes in a stochastic manner. Stochastic choice of the AWCON subtype is established using gap junctions and SLO BK potassium channels to repress a calcium-activated protein kinase pathway. However, it is unknown how the potassium channel-repressed calcium signaling is translated into the induction of the AWCON subtype. Here, we identify a detailed working mechanism of how the homeodomain-like transcription factor NSY-7, previously described as a repressor in the maintenance of AWC asymmetry, couples SLO BK potassium channels to transactivation of sox-2 expression for the induction of the AWCON subtype through the identification of a unique imb-2 (transportin 1) allele. imb-2 loss-of-function mutants are not viable; however, we identify a viable imb-2 allele from an unbiased forward genetic screen that reveals a specific role of imb-2 in AWC olfactory neuron asymmetry. IMB-2 specifically drives nuclear import of NSY-7 within AWC neurons to transactivate the expression of the high mobility group (HMG)-box transcription factor SOX-2 for the specification of the AWCON subtype. This study provides mechanistic insight into how NSY-7 couples SLO BK potassium channels to transactivation of sox-2 expression for the induction of the AWCON subtype. Our findings also provide structure-function insight into a conserved amino acid residue of transportins in brain development and suggest its dysfunction may lead to human neurological disorders.
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25
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Voelker L, Upadhyaya B, Ferkey DM, Woldemariam S, L’Etoile ND, Rabinowitch I, Bai J. INX-18 and INX-19 play distinct roles in electrical synapses that modulate aversive behavior in Caenorhabditis elegans. PLoS Genet 2019; 15:e1008341. [PMID: 31658255 PMCID: PMC6837551 DOI: 10.1371/journal.pgen.1008341] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/07/2019] [Accepted: 10/04/2019] [Indexed: 12/23/2022] Open
Abstract
In order to respond to changing environments and fluctuations in internal states, animals adjust their behavior through diverse neuromodulatory mechanisms. In this study we show that electrical synapses between the ASH primary quinine-detecting sensory neurons and the neighboring ASK neurons are required for modulating the aversive response to the bitter tastant quinine in C. elegans. Mutant worms that lack the electrical synapse proteins INX-18 and INX-19 become hypersensitive to dilute quinine. Cell-specific rescue experiments indicate that inx-18 operates in ASK while inx-19 is required in both ASK and ASH for proper quinine sensitivity. Imaging analyses find that INX-19 in ASK and ASH localizes to the same regions in the nerve ring, suggesting that both sides of ASK-ASH electrical synapses contain INX-19. While inx-18 and inx-19 mutant animals have a similar behavioral phenotype, several lines of evidence suggest the proteins encoded by these genes play different roles in modulating the aversive quinine response. First, INX-18 and INX-19 localize to different regions of the nerve ring, indicating that they are not present in the same synapses. Second, removing inx-18 disrupts the distribution of INX-19, while removing inx-19 does not alter INX-18 localization. Finally, by using a fluorescent cGMP reporter, we find that INX-18 and INX-19 have distinct roles in establishing cGMP levels in ASK and ASH. Together, these results demonstrate that electrical synapses containing INX-18 and INX-19 facilitate modulation of ASH nociceptive signaling. Our findings support the idea that a network of electrical synapses mediates cGMP exchange between neurons, enabling modulation of sensory responses and behavior. Animals are constantly adjusting their behavior to respond to changes in the environment or to their internal state. This behavior modulation is achieved by altering the activity of neurons and circuits through a variety of neuroplasticity mechanisms. Chemical synapses are known to impact neuroplasticity in several different ways, but the diversity of mechanisms by which electrical synapses contribute is still being investigated. Electrical synapses are specialized sites of connection between neurons where ions and small signaling molecules can pass directly from one cell to the next. By passing small molecules through electrical synapses, neurons may be able to modify the activity of their neighbors. In this study we identify two genes that contribute to electrical synapses between two sensory neurons in C. elegans. We show that these electrical synapses are crucial for proper modulation of sensory responses, as without them animals are overly responsive to an aversive stimulus. In addition to pinpointing their sites of action, we present evidence that they may be contributing to neuromodulation by facilitating passage of the small molecule cGMP between neurons. Our work provides evidence for a role of electrical synapses in regulating animal behavior.
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Affiliation(s)
- Lisa Voelker
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA, United States of America
| | - Bishal Upadhyaya
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
| | - Denise M. Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY, United States of America
| | - Sarah Woldemariam
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, United States of America
| | - Noelle D. L’Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, United States of America
| | - Ithai Rabinowitch
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
- Department of Medical Neurobiology, Faculty of Medicine Hebrew, University of Jerusalem, Jerusalem, Israel
| | - Jihong Bai
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States of America
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA, United States of America
- * E-mail:
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26
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Abstract
Consistent asymmetries between the left and right sides of animal bodies are common. For example, the internal organs of vertebrates are left-right (L-R) asymmetric in a stereotyped fashion. Other structures, such as the skeleton and muscles, are largely symmetric. This Review considers how symmetries and asymmetries form alongside each other within the embryo, and how they are then maintained during growth. I describe how asymmetric signals are generated in the embryo. Using the limbs and somites as major examples, I then address mechanisms for protecting symmetrically forming tissues from asymmetrically acting signals. These examples reveal that symmetry should not be considered as an inherent background state, but instead must be actively maintained throughout multiple phases of embryonic patterning and organismal growth.
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Affiliation(s)
- Daniel T Grimes
- Institute of Molecular Biology, Department of Biology, University of Oregon, Eugene, OR 97403, USA
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27
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Worthy SE, Rojas GL, Taylor CJ, Glater EE. Identification of Odor Blend Used by Caenorhabditis elegans for Pathogen Recognition. Chem Senses 2019; 43:169-180. [PMID: 29373666 PMCID: PMC6018680 DOI: 10.1093/chemse/bjy001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Animals have evolved specialized pathways to detect appropriate food sources and avoid harmful ones. Caenorhabditis elegans can distinguish among the odors of various species of bacteria, its major food source, but little is known about what specific chemical cue or combination of chemical cues C. elegans uses to detect and recognize different microbes. Here, we examine the strong innate attraction of C. elegans for the odor of the pathogenic bacterium, Serratia marcescens. This initial attraction likely facilitates ingestion and infection of the C. elegans host. Using solid-phase microextraction and gas chromatography coupled with mass spectrometry, we identify 5 volatile odors released by S. marcescens and identify those that are attractive to C. elegans. We use genetic methods to show that the amphid chemosensory neuron, AWCON, senses both S. marcescens-released 2-butanone and acetone and drives attraction to S. marcescens. In C. elegans, pairing a single odorant with food deprivation results in a reduced attractive response for that specific odor. We find that pairing the natural odor of S. marcescens with food deprivation results in a reduced attraction for the natural odor of S. marcescens and a similar reduced attraction for the synthetic blend of acetone and 2-butanone. This result indicates that only 2 odorants represent the more complex odor bouquet of S. marcescens. Although bacterial-released volatiles have long been known to be attractive to C. elegans, this study defines for the first time specific volatile cues that represent a particular bacterium to C. elegans.
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Affiliation(s)
| | - German L Rojas
- Department of Neuroscience, Pomona College, Claremont, CA, USA
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Multiple Pathways Act Together To Establish Asymmetry of the Ventral Nerve Cord in Caenorhabditis elegans. Genetics 2019; 211:1331-1343. [PMID: 30792268 DOI: 10.1534/genetics.119.301999] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 02/15/2019] [Indexed: 01/30/2023] Open
Abstract
The central nervous system of most animals is bilaterally symmetrical. Closer observation often reveals some functional or anatomical left-right asymmetries. In the nematode Caenorhabditis elegans, the most obvious asymmetry in the nervous system is found in the ventral nerve cord (VNC), where most axons are in the right axon tract. The asymmetry is established when axons entering the VNC from the brain switch from the left to the right side at the anterior end of the VNC. In genetic screens we identified several mutations compromising VNC asymmetry. This includes alleles of col-99 (encoding a transmembrane collagen), unc-52/perlecan and unc-34 (encoding the actin modulator Enabled/Vasodilator-stimulated phosphoproteins). In addition, we evaluated mutants in known axon guidance pathways for asymmetry defects and used genetic interaction studies to place the genes into genetic pathways. In total we identified four different pathways contributing to the establishment of VNC asymmetry, represented by UNC-6/netrin, SAX-3/Robo, COL-99, and EPI-1/laminin. The combined inactivation of these pathways in triple and quadruple mutants leads to highly penetrant VNC asymmetry defects, suggesting these pathways are important contributors to the establishment of VNC asymmetry in C. elegans.
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29
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Li N, van der Kooy D. Mutations in the guanylate cyclase gcy-28 neuronally dissociate naïve attraction and memory retrieval. Eur J Neurosci 2018; 48:3367-3378. [PMID: 30362188 DOI: 10.1111/ejn.14221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 09/26/2018] [Accepted: 10/10/2018] [Indexed: 11/28/2022]
Abstract
The molecules and mechanisms that are involved in the acquisition, storage, and retrieval of memories in many organisms are unclear. To investigate these processes, we use the nematode worm Caenorhabditis elegans, which is attracted naïvely to the odorant benzaldehyde but learns to avoid it after paired exposure with starvation. Mutations in the receptor-like guanylate cyclase GCY-28 have previously been thought to result in a behavioral switch in the primary chemosensory neuron AWCON , from an attractive state to an aversive (already-learned) state. Here, we offer a different interpretation and show that GCY-28 functions in distinct neurons to modulate two independent processes: naïve attraction to AWCON -sensed odors in the AWCON neuron, and associative learning of benzaldehyde and starvation in the AIA interneurons. Consequently, mutants that lack gcy-28 do not approach AWCON -sensed odors and cannot associate benzaldehyde with starvation. We further show that this learning deficit lies in memory retrieval, not in its acquisition or storage, and that GCY-28 is required in AIA for sensory integration only when both AWC neurons (ON and OFF) are activated by chemical stimuli. Our results reveal a novel role of GCY-28 in the retrieval of associative memories and may have wide implications for the neural machineries of learning and memory in general.
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Affiliation(s)
- Naijin Li
- The Donnelly Centre for Cellular and Biomolecular Research, Toronto, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Derek van der Kooy
- The Donnelly Centre for Cellular and Biomolecular Research, Toronto, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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30
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Güiza J, Barría I, Sáez JC, Vega JL. Innexins: Expression, Regulation, and Functions. Front Physiol 2018; 9:1414. [PMID: 30364195 PMCID: PMC6193117 DOI: 10.3389/fphys.2018.01414] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 09/18/2018] [Indexed: 01/02/2023] Open
Abstract
The innexin (Inx) proteins form gap junction channels and non-junctional channels (named hemichannels) in invertebrates. These channels participate in cellular communication playing a relevant role in several physiological processes. Pioneer studies conducted mainly in worms and flies have shown that innexins participate in embryo development and behavior. However, recent studies have elucidated new functions of innexins in Arthropoda, Nematoda, Annelida, and Cnidaria, such as immune response, and apoptosis. This review describes emerging data of possible new roles of innexins and summarizes the data available to date.
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Affiliation(s)
- Juan Güiza
- Laboratorio de Fisiología Experimental, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Iván Barría
- Laboratorio de Fisiología Experimental, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Juan C Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile.,Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - José L Vega
- Laboratorio de Fisiología Experimental, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
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31
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Vidal B, Aghayeva U, Sun H, Wang C, Glenwinkel L, Bayer EA, Hobert O. An atlas of Caenorhabditis elegans chemoreceptor expression. PLoS Biol 2018; 16:e2004218. [PMID: 29293491 PMCID: PMC5749674 DOI: 10.1371/journal.pbio.2004218] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 11/22/2017] [Indexed: 12/20/2022] Open
Abstract
One goal of modern day neuroscience is the establishment of molecular maps that assign unique features to individual neuron types. Such maps provide important starting points for neuron classification, for functional analysis, and for developmental studies aimed at defining the molecular mechanisms of neuron identity acquisition and neuron identity diversification. In this resource paper, we describe a nervous system-wide map of the potential expression sites of 244 members of the largest gene family in the C. elegans genome, rhodopsin-like (class A) G-protein-coupled receptor (GPCR) chemoreceptors, using classic gfp reporter gene technology. We cover representatives of all sequence families of chemoreceptor GPCRs, some of which were previously entirely uncharacterized. Most reporters are expressed in a very restricted number of cells, often just in single cells. We assign GPCR reporter expression to all but two of the 37 sensory neuron classes of the sex-shared, core nervous system. Some sensory neurons express a very small number of receptors, while others, particularly nociceptive neurons, coexpress several dozen GPCR reporter genes. GPCR reporters are also expressed in a wide range of inter- and motorneurons, as well as non-neuronal cells, suggesting that GPCRs may constitute receptors not just for environmental signals, but also for internal cues. We observe only one notable, frequent association of coexpression patterns, namely in one nociceptive amphid (ASH) and two nociceptive phasmid sensory neurons (PHA, PHB). We identified GPCRs with sexually dimorphic expression and several GPCR reporters that are expressed in a left/right asymmetric manner. We identified a substantial degree of GPCR expression plasticity; particularly in the context of the environmentally-induced dauer diapause stage when one third of all tested GPCRs alter the cellular specificity of their expression within and outside the nervous system. Intriguingly, in a number of cases, the dauer-specific alterations of GPCR reporter expression in specific neuron classes are maintained during postdauer life and in some case new patterns are induced post-dauer, demonstrating that GPCR gene expression may serve as traits of life history. Taken together, our resource provides an entry point for functional studies and also offers a host of molecular markers for studying molecular patterning and plasticity of the nervous system.
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Affiliation(s)
- Berta Vidal
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York, United States of America
| | - Ulkar Aghayeva
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York, United States of America
| | - Haosheng Sun
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York, United States of America
| | - Chen Wang
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York, United States of America
| | - Lori Glenwinkel
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York, United States of America
| | - Emily A. Bayer
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York, United States of America
| | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York, United States of America
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32
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Alqadah A, Hsieh YW, Xiong R, Chuang CF. Stochastic left-right neuronal asymmetry in Caenorhabditis elegans. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0407. [PMID: 27821536 DOI: 10.1098/rstb.2015.0407] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2016] [Indexed: 12/28/2022] Open
Abstract
Left-right asymmetry in the nervous system is observed across species. Defects in left-right cerebral asymmetry are linked to several neurological diseases, but the molecular mechanisms underlying brain asymmetry in vertebrates are still not very well understood. The Caenorhabditis elegans left and right amphid wing 'C' (AWC) olfactory neurons communicate through intercellular calcium signalling in a transient embryonic gap junction neural network to specify two asymmetric subtypes, AWCOFF (default) and AWCON (induced), in a stochastic manner. Here, we highlight the molecular mechanisms that establish and maintain stochastic AWC asymmetry. As the components of the AWC asymmetry pathway are highly conserved, insights from the model organism C. elegans may provide a window onto how brain asymmetry develops in humans.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.
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Affiliation(s)
- Amel Alqadah
- Department of Biological Sciences, University of Illinois at Chicago, IL 60607, USA
| | - Yi-Wen Hsieh
- Department of Biological Sciences, University of Illinois at Chicago, IL 60607, USA
| | - Rui Xiong
- Department of Biological Sciences, University of Illinois at Chicago, IL 60607, USA
| | - Chiou-Fen Chuang
- Department of Biological Sciences, University of Illinois at Chicago, IL 60607, USA
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33
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Alqadah A, Hsieh YW, Morrissey ZD, Chuang CF. Asymmetric development of the nervous system. Dev Dyn 2017; 247:124-137. [PMID: 28940676 DOI: 10.1002/dvdy.24595] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 09/09/2017] [Accepted: 09/18/2017] [Indexed: 12/13/2022] Open
Abstract
The human nervous system consists of seemingly symmetric left and right halves. However, closer observation of the brain reveals anatomical and functional lateralization. Defects in brain asymmetry correlate with several neurological disorders, yet our understanding of the mechanisms used to establish lateralization in the human central nervous system is extremely limited. Here, we review left-right asymmetries within the nervous system of humans and several model organisms, including rodents, Zebrafish, chickens, Xenopus, Drosophila, and the nematode Caenorhabditis elegans. Comparing and contrasting mechanisms used to develop left-right asymmetry in the nervous system can provide insight into how the human brain is lateralized. Developmental Dynamics 247:124-137, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Amel Alqadah
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois
| | - Yi-Wen Hsieh
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois
| | - Zachery D Morrissey
- Graduate Program in Neuroscience, University of Illinois at Chicago, Chicago, Illinois
| | - Chiou-Fen Chuang
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois.,Graduate Program in Neuroscience, University of Illinois at Chicago, Chicago, Illinois
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34
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The role of gap junctions in the C. elegans connectome. Neurosci Lett 2017; 695:12-18. [PMID: 28886984 DOI: 10.1016/j.neulet.2017.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/12/2017] [Accepted: 09/01/2017] [Indexed: 10/18/2022]
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35
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Otopalik AG, Lane B, Schulz DJ, Marder E. Innexin expression in electrically coupled motor circuits. Neurosci Lett 2017; 695:19-24. [PMID: 28711343 PMCID: PMC5767152 DOI: 10.1016/j.neulet.2017.07.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 06/22/2017] [Accepted: 07/11/2017] [Indexed: 12/21/2022]
Abstract
The many roles of innexins, the molecules that form gap junctions in invertebrates, have been explored in numerous species. Here, we present a summary of innexin expression and function in two small, central pattern generating circuits found in crustaceans: the stomatogastric ganglion and the cardiac ganglion. The two ganglia express multiple innexin genes, exhibit varying combinations of symmetrical and rectifying gap junctions, as well as gap junctions within and across different cell types. Past studies have revealed correlations in ion channel and innexin expression in coupled neurons, as well as intriguing functional relationships between ion channel conductances and electrical coupling. Together, these studies suggest a putative role for innexins in correlating activity between coupled neurons at the levels of gene expression and physiological activity during development and in the adult animal.
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Affiliation(s)
- Adriane G Otopalik
- Volen Center and Biology Department, Brandeis University, Waltham, MA 02454, USA.
| | - Brian Lane
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO, 65211, USA
| | - David J Schulz
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO, 65211, USA
| | - Eve Marder
- Volen Center and Biology Department, Brandeis University, Waltham, MA 02454, USA
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36
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Mathews J, Levin M. Gap junctional signaling in pattern regulation: Physiological network connectivity instructs growth and form. Dev Neurobiol 2017; 77:643-673. [PMID: 27265625 PMCID: PMC10478170 DOI: 10.1002/dneu.22405] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/27/2016] [Accepted: 05/31/2016] [Indexed: 12/19/2022]
Abstract
Gap junctions (GJs) are aqueous channels that allow cells to communicate via physiological signals directly. The role of gap junctional connectivity in determining single-cell functions has long been recognized. However, GJs have another important role: the regulation of large-scale anatomical pattern. GJs are not only versatile computational elements that allow cells to control which small molecule signals they receive and emit, but also establish connectivity patterns within large groups of cells. By dynamically regulating the topology of bioelectric networks in vivo, GJs underlie the ability of many tissues to implement complex morphogenesis. Here, a review of recent data on patterning roles of GJs in growth of the zebrafish fin, the establishment of left-right patterning, the developmental dysregulation known as cancer, and the control of large-scale head-tail polarity, and head shape in planarian regeneration has been reported. A perspective in which GJs are not only molecular features functioning in single cells, but also enable global neural-like dynamics in non-neural somatic tissues has been proposed. This view suggests a rich program of future work which capitalizes on the rapid advances in the biophysics of GJs to exploit GJ-mediated global dynamics for applications in birth defects, regenerative medicine, and morphogenetic bioengineering. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 643-673, 2017.
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Affiliation(s)
- Juanita Mathews
- Department of Biology, Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, MA
| | - Michael Levin
- Department of Biology, Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, MA
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37
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Hall DH. Gap junctions in C. elegans: Their roles in behavior and development. Dev Neurobiol 2017; 77:587-596. [PMID: 27294317 PMCID: PMC5412865 DOI: 10.1002/dneu.22408] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 06/08/2016] [Accepted: 06/08/2016] [Indexed: 01/07/2023]
Abstract
The nematode Caenorhabditis elegans utilizes gap junctions in different fashions in virtually all of its cells. This model animal has a surprisingly large number of innexin genes within its genome, and many nematode cell types can express multiple innexins at once, leading to the formation of diverse junction types and enough redundancy to limit the effect of single gene knockdowns on animal development or behavioral phenotypes. Here, we review the general properties of these junctions, their expression patterns, and their known roles in tissue development and in the animal's connectome. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 587-596, 2017.
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Affiliation(s)
- David H Hall
- Department of Neuroscience, Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, New York, 10461
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38
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Hsieh YW, Alqadah A, Chuang CF. Mechanisms controlling diversification of olfactory sensory neuron classes. Cell Mol Life Sci 2017; 74:3263-3274. [PMID: 28357469 DOI: 10.1007/s00018-017-2512-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 02/28/2017] [Accepted: 03/21/2017] [Indexed: 12/25/2022]
Abstract
Animals survive in harsh and fluctuating environments using sensory neurons to detect and respond to changes in their surroundings. Olfactory sensory neurons are essential for detecting food, identifying danger, and sensing pheromones. The ability to sense a large repertoire of different types of odors is crucial to distinguish between different situations, and is achieved through neuronal diversity within the olfactory system. Here, we review the developmental mechanisms used to establish diversity of olfactory sensory neurons in various model organisms, including Caenorhabditis elegans, Drosophila, and vertebrate models. Understanding and comparing how different olfactory neurons develop within the nervous system of different animals can provide insight into how the olfactory system is shaped in humans.
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Affiliation(s)
- Yi-Wen Hsieh
- Department of Biological Sciences, University of Illinois at Chicago, 900 S. Ashland Avenue, MC 567, Chicago, IL, 60607, USA
| | - Amel Alqadah
- Department of Biological Sciences, University of Illinois at Chicago, 900 S. Ashland Avenue, MC 567, Chicago, IL, 60607, USA
| | - Chiou-Fen Chuang
- Department of Biological Sciences, University of Illinois at Chicago, 900 S. Ashland Avenue, MC 567, Chicago, IL, 60607, USA.
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39
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Dissection of neuronal gap junction circuits that regulate social behavior in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2017; 114:E1263-E1272. [PMID: 28143932 DOI: 10.1073/pnas.1621274114] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
A hub-and-spoke circuit of neurons connected by gap junctions controls aggregation behavior and related behavioral responses to oxygen, pheromones, and food in Caenorhabditis elegans The molecular composition of the gap junctions connecting RMG hub neurons with sensory spoke neurons is unknown. We show here that the innexin gene unc-9 is required in RMG hub neurons to drive aggregation and related behaviors, indicating that UNC-9-containing gap junctions mediate RMG signaling. To dissect the circuit in detail, we developed methods to inhibit unc-9-based gap junctions with dominant-negative unc-1 transgenes. unc-1(dn) alters a stomatin-like protein that regulates unc-9 electrical signaling; its disruptive effects can be rescued by a constitutively active UNC-9::GFP protein, demonstrating specificity. Expression of unc-1(dn) in RMG hub neurons, ADL or ASK pheromone-sensing neurons, or URX oxygen-sensing neurons disrupts specific elements of aggregation-related behaviors. In ADL, unc-1(dn) has effects opposite to those of tetanus toxin light chain, separating the roles of ADL electrical and chemical synapses. These results reveal roles of gap junctions in a complex behavior at cellular resolution and provide a tool for similar exploration of other gap junction circuits.
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40
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Sahu A, Ghosh R, Deshpande G, Prasad M. A Gap Junction Protein, Inx2, Modulates Calcium Flux to Specify Border Cell Fate during Drosophila oogenesis. PLoS Genet 2017; 13:e1006542. [PMID: 28114410 PMCID: PMC5256874 DOI: 10.1371/journal.pgen.1006542] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 12/15/2016] [Indexed: 01/09/2023] Open
Abstract
Intercellular communication mediated by gap junction (GJ) proteins is indispensable during embryogenesis, tissue regeneration and wound healing. Here we report functional analysis of a gap junction protein, Innexin 2 (Inx2), in cell type specification during Drosophila oogenesis. Our data reveal a novel involvement of Inx2 in the specification of Border Cells (BCs), a migratory cell type, whose identity is determined by the cell autonomous STAT activity. We show that Inx2 influences BC fate specification by modulating STAT activity via Domeless receptor endocytosis. Furthermore, detailed experimental analysis has uncovered that Inx2 also regulates a calcium flux that transmits across the follicle cells. We propose that Inx2 mediated calcium flux in the follicle cells stimulates endocytosis by altering Dynamin (Shibire) distribution which is in turn critical for careful calibration of STAT activation and, thus for BC specification. Together our data provide unprecedented molecular insights into how gap junction proteins can regulate cell-type specification. Gap junction mediated intercellular communication modulates several processes during development, morphogenesis and normal tissue homeostasis. While gap junction proteins play an important role during intercellular communication, the underlying molecular mechanism(s) as to how they regulate diverse signaling cascades are unclear. By employing the Drosophila melanogaster oogenesis model we have characterized the role of gap junction protein, Innexin 2 (Inx2), in cell fate specification during Drosophila oogenesis. Our data demonstrate that loss of inx2 affects border cell specification. Border cells are a small group of 6–8 follicle cells that acquire migratory fate in response to the activation of JAK-STAT signaling. We show that perturbing Inx2 levels in the follicle cells inhibits JAK-STAT signaling thereby adversely influencing border cell fate specification. Using live cell imaging and molecular genetic analysis, we have elucidated the molecular mechanism underlying Inx2 function in this process. We show that Inx2 mediates inter-follicular calcium flux that is critical for border cell fate determination. Furthermore, our observations indicate that Inx2 regulates Domeless receptor internalization possibly via influencing distribution of Drosophila Dynamin, Shibire in the follicle cells. Taken together these results suggest a functional link between Inx2, calcium flux and receptor endocytosis during border cell fate specification in Drosophila oogenesis.
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Affiliation(s)
- Aresh Sahu
- Department of Biological Sciences Indian Institute of Science Education & Research Kolkata Mohanpur Campus Mohanpur, Nadia, West Bengal, India
| | - Ritabrata Ghosh
- Department of Biological Sciences Indian Institute of Science Education & Research Kolkata Mohanpur Campus Mohanpur, Nadia, West Bengal, India
| | - Girish Deshpande
- Department of Molecular Biology Princeton University, Princeton, NJ, United States of America
- Indian Institute of Science Education and Research Pune. Pune Maharashtra, India
| | - Mohit Prasad
- Department of Biological Sciences Indian Institute of Science Education & Research Kolkata Mohanpur Campus Mohanpur, Nadia, West Bengal, India
- * E-mail:
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41
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Alcorn MR, Callander DC, López-Santos A, Torres Cleuren YN, Birsoy B, Joshi PM, Santure AW, Rothman JH. Heterotaxy in Caenorhabditis: widespread natural variation in left-right arrangement of the major organs. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150404. [PMID: 27821534 PMCID: PMC5104504 DOI: 10.1098/rstb.2015.0404] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2016] [Indexed: 12/13/2022] Open
Abstract
Although the arrangement of internal organs in most metazoans is profoundly left-right (L/R) asymmetric with a predominant handedness, rare individuals show full (mirror-symmetric) or partial (heterotaxy) reversals. While the nematode Caenorhabditis elegans is known for its highly determinate development, including stereotyped L/R organ handedness, we found that L/R asymmetry of the major organs, the gut and gonad, varies among natural isolates of the species in both males and hermaphrodites. In hermaphrodites, heterotaxy can involve one or both bilaterally asymmetric gonad arms. Male heterotaxy is probably not attributable to relaxed selection in this hermaphroditic species, as it is also seen in gonochoristic Caenorhabditis species. Heterotaxy increases in many isolates at elevated temperature, with one showing a pregastrulation temperature-sensitive period, suggesting a very early embryonic or germline effect on this much later developmental outcome. A genome-wide association study of 100 isolates showed that male heterotaxy is associated with three genomic regions. Analysis of recombinant inbred lines suggests that a small number of loci are responsible for the observed variation. These findings reveal that heterotaxy is a widely varying quantitative trait in an animal with an otherwise highly stereotyped anatomy, demonstrating unexpected plasticity in an L/R arrangement of the major organs even in a simple animal.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.
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Affiliation(s)
- Melissa R Alcorn
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA
| | - Davon C Callander
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA
| | | | - Yamila N Torres Cleuren
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Bilge Birsoy
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA
- Department of MCD Biology, University of Colorado, Boulder, CO 80309-0347, USA
| | - Pradeep M Joshi
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA
| | - Anna W Santure
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Joel H Rothman
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
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42
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Meng L, Zhang A, Jin Y, Yan D. Regulation of neuronal axon specification by glia-neuron gap junctions in C. elegans. eLife 2016; 5. [PMID: 27767956 PMCID: PMC5083064 DOI: 10.7554/elife.19510] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 10/20/2016] [Indexed: 01/22/2023] Open
Abstract
Axon specification is a critical step in neuronal development, and the function of glial cells in this process is not fully understood. Here, we show that C. elegans GLR glial cells regulate axon specification of their nearby GABAergic RME neurons through GLR-RME gap junctions. Disruption of GLR-RME gap junctions causes misaccumulation of axonal markers in non-axonal neurites of RME neurons and converts microtubules in those neurites to form an axon-like assembly. We further uncover that GLR-RME gap junctions regulate RME axon specification through activation of the CDK-5 pathway in a calcium-dependent manner, involving a calpain clp-4. Therefore, our study reveals the function of glia-neuron gap junctions in neuronal axon specification and shows that calcium originated from glial cells can regulate neuronal intracellular pathways through gap junctions.
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Affiliation(s)
- Lingfeng Meng
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, United States.,Department of Neurobiology, Duke University Medical Center, Durham, United States.,Duke Institute for Brain Sciences, Duke Medical Center, Durham, United States
| | - Albert Zhang
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, United States.,Department of Neurobiology, Duke University Medical Center, Durham, United States.,Duke Institute for Brain Sciences, Duke Medical Center, Durham, United States
| | - Yishi Jin
- Neurobiology Section, Division of Biological Sciences, Howard Hughes Medical Institute, University of California, San Diego, United States.,Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, United States
| | - Dong Yan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, United States.,Department of Neurobiology, Duke University Medical Center, Durham, United States.,Duke Institute for Brain Sciences, Duke Medical Center, Durham, United States
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Krzyzanowski MC, Woldemariam S, Wood JF, Chaubey AH, Brueggemann C, Bowitch A, Bethke M, L’Etoile ND, Ferkey DM. Aversive Behavior in the Nematode C. elegans Is Modulated by cGMP and a Neuronal Gap Junction Network. PLoS Genet 2016; 12:e1006153. [PMID: 27459302 PMCID: PMC4961389 DOI: 10.1371/journal.pgen.1006153] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 06/08/2016] [Indexed: 01/03/2023] Open
Abstract
All animals rely on their ability to sense and respond to their environment to survive. However, the suitability of a behavioral response is context-dependent, and must reflect both an animal's life history and its present internal state. Based on the integration of these variables, an animal's needs can be prioritized to optimize survival strategies. Nociceptive sensory systems detect harmful stimuli and allow for the initiation of protective behavioral responses. The polymodal ASH sensory neurons are the primary nociceptors in C. elegans. We show here that the guanylyl cyclase ODR-1 functions non-cell-autonomously to downregulate ASH-mediated aversive behaviors and that ectopic cGMP generation in ASH is sufficient to dampen ASH sensitivity. We define a gap junction neural network that regulates nociception and propose that decentralized regulation of ASH signaling can allow for rapid correlation between an animal's internal state and its behavioral output, lending modulatory flexibility to this hard-wired nociceptive neural circuit.
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Affiliation(s)
- Michelle C. Krzyzanowski
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, New York, United States of America
| | - Sarah Woldemariam
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, United States of America
| | - Jordan F. Wood
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, New York, United States of America
| | - Aditi H. Chaubey
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, New York, United States of America
| | - Chantal Brueggemann
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, United States of America
| | - Alexander Bowitch
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, New York, United States of America
| | - Mary Bethke
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, United States of America
| | - Noelle D. L’Etoile
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, United States of America
| | - Denise M. Ferkey
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, New York, United States of America
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44
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Durant F, Lobo D, Hammelman J, Levin M. Physiological controls of large-scale patterning in planarian regeneration: a molecular and computational perspective on growth and form. REGENERATION (OXFORD, ENGLAND) 2016; 3:78-102. [PMID: 27499881 PMCID: PMC4895326 DOI: 10.1002/reg2.54] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/18/2016] [Accepted: 02/22/2016] [Indexed: 12/12/2022]
Abstract
Planaria are complex metazoans that repair damage to their bodies and cease remodeling when a correct anatomy has been achieved. This model system offers a unique opportunity to understand how large-scale anatomical homeostasis emerges from the activities of individual cells. Much progress has been made on the molecular genetics of stem cell activity in planaria. However, recent data also indicate that the global pattern is regulated by physiological circuits composed of ionic and neurotransmitter signaling. Here, we overview the multi-scale problem of understanding pattern regulation in planaria, with specific focus on bioelectric signaling via ion channels and gap junctions (electrical synapses), and computational efforts to extract explanatory models from functional and molecular data on regeneration. We present a perspective that interprets results in this fascinating field using concepts from dynamical systems theory and computational neuroscience. Serving as a tractable nexus between genetic, physiological, and computational approaches to pattern regulation, planarian pattern homeostasis harbors many deep insights for regenerative medicine, evolutionary biology, and engineering.
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Affiliation(s)
- Fallon Durant
- Department of Biology, Allen Discovery Center at Tufts University, Tufts Center for Regenerative and Developmental BiologyTufts UniversityMA02155USA
| | - Daniel Lobo
- Department of Biological SciencesUniversity of MarylandBaltimore County, 1000 Hilltop CircleBaltimoreMD21250USA
| | - Jennifer Hammelman
- Department of Biology, Allen Discovery Center at Tufts University, Tufts Center for Regenerative and Developmental BiologyTufts UniversityMA02155USA
| | - Michael Levin
- Department of Biology, Allen Discovery Center at Tufts University, Tufts Center for Regenerative and Developmental BiologyTufts UniversityMA02155USA
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45
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Meng L, Chen CH, Yan D. Regulation of Gap Junction Dynamics by UNC-44/ankyrin and UNC-33/CRMP through VAB-8 in C. elegans Neurons. PLoS Genet 2016; 12:e1005948. [PMID: 27015090 PMCID: PMC4807823 DOI: 10.1371/journal.pgen.1005948] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 03/01/2016] [Indexed: 11/18/2022] Open
Abstract
Gap junctions are present in both vertebrates and invertebrates from nematodes to mammals. Although the importance of gap junctions has been documented in many biological processes, the molecular mechanisms underlying gap junction dynamics remain unclear. Here, using the C. elegans PLM neurons as a model, we show that UNC-44/ankyrin acts upstream of UNC-33/CRMP in regulation of a potential kinesin VAB-8 to control gap junction dynamics, and loss-of-function in the UNC-44/UNC-33/VAB-8 pathway suppresses the turnover of gap junction channels. Therefore, we first show a signal pathway including ankyrin, CRMP, and kinesin in regulating gap junctions.
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Affiliation(s)
- Lingfeng Meng
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Chia-hui Chen
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Neurobiology and Duke Institute for Brain Sciences, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Dong Yan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Neurobiology and Duke Institute for Brain Sciences, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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46
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Chrisman SD, Waite CB, Scoville AG, Carnell L. C. elegans Demonstrates Distinct Behaviors within a Fixed and Uniform Electric Field. PLoS One 2016; 11:e0151320. [PMID: 26998749 PMCID: PMC4801214 DOI: 10.1371/journal.pone.0151320] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 02/26/2016] [Indexed: 01/20/2023] Open
Abstract
C. elegans will orient and travel in a straight uninterrupted path directly towards the negative pole of a DC electric field. We have sought to understand the strategy worms use to navigate to the negative pole in a uniform electric field that is fixed in both direction and magnitude. We examined this behavior by quantifying three aspects of electrotaxis behavior in response to different applied field strengths: the mean approach trajectory angles of the animals’ tracks, turning behavior (pirouettes) and average population speeds. We determined that C. elegans align directly to the negative pole of an electric field at sub-preferred field strength and alter approach trajectories at higher field strengths to maintain taxis within a preferred range we have calculated to be ~ 5V/cm. We sought to identify the sensory neurons responsible for the animals’ tracking to a preferred field strength. eat-4 mutant animals defective in glutamatergic signaling of the amphid sensory neurons are severely electrotaxis defective and ceh-36 mutant animals, which are defective in the terminal differentiation of two types of sensory neurons, AWC and ASE, are partially defective in electrotaxis. To further elucidate the role of the AWC neurons, we examined the role of each of the pair of AWC neurons (AWCOFF and AWCON), which are functionally asymmetric and express different genes. nsy-5/inx-19 mutant animals, which express both neurons as AWCOFF, are severely impaired in electrotaxis behavior while nsy-1 mutants, which express both neurons as AWCON, are able to differentiate field strengths required for navigation to a specific field strength within an electric field. We also tested a strain with targeted genetic ablation of AWC neurons and found that these animals showed only slight disruption of directionality and turning behavior. These results suggest a role for AWC neurons in which complete loss of function is less disruptive than loss of functional asymmetry in electrotaxis behavior within a uniform fixed field.
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Affiliation(s)
- Steven D. Chrisman
- Department of Biological Sciences, Central Washington University, Ellensburg, Washington, United States of America
| | - Christopher B. Waite
- Department of Biological Sciences, Central Washington University, Ellensburg, Washington, United States of America
| | - Alison G. Scoville
- Department of Biological Sciences, Central Washington University, Ellensburg, Washington, United States of America
| | - Lucinda Carnell
- Department of Biological Sciences, Central Washington University, Ellensburg, Washington, United States of America
- * E-mail:
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47
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Alqadah A, Hsieh YW, Schumacher JA, Wang X, Merrill SA, Millington G, Bayne B, Jorgensen EM, Chuang CF. SLO BK Potassium Channels Couple Gap Junctions to Inhibition of Calcium Signaling in Olfactory Neuron Diversification. PLoS Genet 2016; 12:e1005654. [PMID: 26771544 PMCID: PMC4714817 DOI: 10.1371/journal.pgen.1005654] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 10/16/2015] [Indexed: 01/09/2023] Open
Abstract
The C. elegans AWC olfactory neuron pair communicates to specify asymmetric subtypes AWCOFF and AWCON in a stochastic manner. Intercellular communication between AWC and other neurons in a transient NSY-5 gap junction network antagonizes voltage-activated calcium channels, UNC-2 (CaV2) and EGL-19 (CaV1), in the AWCON cell, but how calcium signaling is downregulated by NSY-5 is only partly understood. Here, we show that voltage- and calcium-activated SLO BK potassium channels mediate gap junction signaling to inhibit calcium pathways for asymmetric AWC differentiation. Activation of vertebrate SLO-1 channels causes transient membrane hyperpolarization, which makes it an important negative feedback system for calcium entry through voltage-activated calcium channels. Consistent with the physiological roles of SLO-1, our genetic results suggest that slo-1 BK channels act downstream of NSY-5 gap junctions to inhibit calcium channel-mediated signaling in the specification of AWCON. We also show for the first time that slo-2 BK channels are important for AWC asymmetry and act redundantly with slo-1 to inhibit calcium signaling. In addition, nsy-5-dependent asymmetric expression of slo-1 and slo-2 in the AWCON neuron is necessary and sufficient for AWC asymmetry. SLO-1 and SLO-2 localize close to UNC-2 and EGL-19 in AWC, suggesting a role of possible functional coupling between SLO BK channels and voltage-activated calcium channels in AWC asymmetry. Furthermore, slo-1 and slo-2 regulate the localization of synaptic markers, UNC-2 and RAB-3, in AWC neurons to control AWC asymmetry. We also identify the requirement of bkip-1, which encodes a previously identified auxiliary subunit of SLO-1, for slo-1 and slo-2 function in AWC asymmetry. Together, these results provide an unprecedented molecular link between gap junctions and calcium pathways for terminal differentiation of olfactory neurons.
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Affiliation(s)
- Amel Alqadah
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
- Molecular and Developmental Biology Graduate Program, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Yi-Wen Hsieh
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Jennifer A. Schumacher
- Division of Developmental Biology, Cincinnati Children’s Hospital Research Foundation, Cincinnati, Ohio, United States of America
| | - Xiaohong Wang
- Division of Developmental Biology, Cincinnati Children’s Hospital Research Foundation, Cincinnati, Ohio, United States of America
| | - Sean A. Merrill
- Department of Biology and Howard Hughes Medical Institute, University of Utah, Salt Lake City, Utah, United States of America
| | - Grethel Millington
- Molecular and Developmental Biology Graduate Program, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Brittany Bayne
- Division of Developmental Biology, Cincinnati Children’s Hospital Research Foundation, Cincinnati, Ohio, United States of America
| | - Erik M. Jorgensen
- Department of Biology and Howard Hughes Medical Institute, University of Utah, Salt Lake City, Utah, United States of America
| | - Chiou-Fen Chuang
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
- * E-mail:
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48
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Liu Z, Ciarleglio CM, Hamodi AS, Aizenman CD, Pratt KG. A population of gap junction-coupled neurons drives recurrent network activity in a developing visual circuit. J Neurophysiol 2016; 115:1477-86. [PMID: 26763780 DOI: 10.1152/jn.01046.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 01/08/2016] [Indexed: 01/04/2023] Open
Abstract
In many regions of the vertebrate brain, microcircuits generate local recurrent activity that aids in the processing and encoding of incoming afferent inputs. Local recurrent activity can amplify, filter, and temporally and spatially parse out incoming input. Determining how these microcircuits function is of great interest because it provides glimpses into fundamental processes underlying brain computation. Within the Xenopus tadpole optic tectum, deep layer neurons display robust recurrent activity. Although the development and plasticity of this local recurrent activity has been well described, the underlying microcircuitry is not well understood. Here, using a whole brain preparation that allows for whole cell recording from neurons of the superficial tectal layers, we identified a physiologically distinct population of excitatory neurons that are gap junctionally coupled and through this coupling gate local recurrent network activity. Our findings provide a novel role for neuronal coupling among excitatory interneurons in the temporal processing of visual stimuli.
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Affiliation(s)
- Zhenyu Liu
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming; and
| | | | - Ali S Hamodi
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming; and
| | - Carlos D Aizenman
- Department of Neuroscience, Brown University, Providence, Rhode Island
| | - Kara G Pratt
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming; and
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49
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Alqadah A, Hsieh YW, Vidal B, Chang C, Hobert O, Chuang CF. Postmitotic diversification of olfactory neuron types is mediated by differential activities of the HMG-box transcription factor SOX-2. EMBO J 2015; 34:2574-89. [PMID: 26341465 DOI: 10.15252/embj.201592188] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/06/2015] [Indexed: 12/23/2022] Open
Abstract
Diversification of neuron classes is essential for functions of the olfactory system, but the underlying mechanisms that generate individual olfactory neuron types are only beginning to be understood. Here we describe a role of the highly conserved HMG-box transcription factor SOX-2 in postmitotic specification and alternative differentiation of the Caenorhabditis elegans AWC and AWB olfactory neurons. We show that SOX-2 partners with different transcription factors to diversify postmitotic olfactory cell types. SOX-2 functions cooperatively with the OTX/OTD transcription factor CEH-36 to specify an AWC "ground state," and functions with the LIM homeodomain factor LIM-4 to suppress this ground state and drive an AWB identity instead. Our findings provide novel insights into combinatorial codes that drive terminal differentiation programs in the nervous system and reveal a biological function of the deeply conserved Sox2 protein that goes beyond its well-known role in stem cell biology.
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Affiliation(s)
- Amel Alqadah
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA Molecular and Developmental Biology Graduate Program, University of Cincinnati, Cincinnati, OH, USA
| | - Yi-Wen Hsieh
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Berta Vidal
- Department of Biological Sciences, Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute Columbia University, New York, NY, USA
| | - Chieh Chang
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Oliver Hobert
- Department of Biological Sciences, Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute Columbia University, New York, NY, USA
| | - Chiou-Fen Chuang
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
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50
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Werner KM, Perez LJ, Ghosh R, Semmelhack MF, Bassler BL. Caenorhabditis elegans recognizes a bacterial quorum-sensing signal molecule through the AWCON neuron. J Biol Chem 2014; 289:26566-26573. [PMID: 25092291 PMCID: PMC4176233 DOI: 10.1074/jbc.m114.573832] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Revised: 07/11/2014] [Indexed: 11/06/2022] Open
Abstract
In a process known as quorum sensing, bacteria use chemicals called autoinducers for cell-cell communication. Population-wide detection of autoinducers enables bacteria to orchestrate collective behaviors. In the animal kingdom detection of chemicals is vital for success in locating food, finding hosts, and avoiding predators. This behavior, termed chemotaxis, is especially well studied in the nematode Caenorhabditis elegans. Here we demonstrate that the Vibrio cholerae autoinducer (S)-3-hydroxytridecan-4-one, termed CAI-1, influences chemotaxis in C. elegans. C. elegans prefers V. cholerae that produces CAI-1 over a V. cholerae mutant defective for CAI-1 production. The position of the CAI-1 ketone moiety is the key feature driving CAI-1-directed nematode behavior. CAI-1 is detected by the C. elegans amphid sensory neuron AWC(ON). Laser ablation of the AWC(ON) cell, but not other amphid sensory neurons, abolished chemoattraction to CAI-1. These analyses define the structural features of a bacterial-produced signal and the nematode chemosensory neuron that permit cross-kingdom interaction.
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Affiliation(s)
- Kristen M Werner
- Department of Molecular Biology and Princeton University, Princeton, New Jersey 08544
| | - Lark J Perez
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, New Jersey 08028
| | - Rajarshi Ghosh
- Department of Pediatrics-Oncology, Baylor College of Medicine, Houston, Texas 77030, and
| | | | - Bonnie L Bassler
- Department of Molecular Biology and Princeton University, Princeton, New Jersey 08544; Howard Hughes Medical Institute, Chevy Chase, Maryland 20815.
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